Tad Cummins and Elizabeth Thomas were spotted in Oklahoma City on March 15. (Source: TBI)

NASHVILLE, TN (WSMV) -

The focus of the search for 15-year-old Elizabeth Thomas and her former teacher has shifted after the TBI confirmed both were spotted in Oklahoma City on March 15.

Prior to this, Thomas was last seen being dropped off by a friend at the Shoney’s in Columbia around 8 a.m. on March 13.

Since then, the FBI has joined the investigation and Amber Alerts have been issued for Thomas in both Tennessee and Alabama.

The TBI said Thomas and 50-year-old Tad Cummins were seen shopping at a Walmart in Oklahoma City, OK, on March 15. Click here to read more.

At this point, the Tennessee Bureau of Investigation has received more than 1,200 leads about the pair, but the only confirmed sighting has taken place in Oklahoma City.

Officials said they have been in contact with authorities in Mexico and Central America but have no specific information that the pair has crossed the border. District Attorney Brent Cooper said Cummins is well versed in the Bible and could be posing as a missionary.

In a news conference earlier this week, TBI spokesman Josh DeVine urged the public to report tips as soon as possible. DeVine said many of the leads the TBI has received came in too late for authorities to verify.

Although it's been two weeks since Thomas and Cummins vanished, authorities are asking the public to stay aware and alert.

TBI Director Mark Gwyn is trying to make sure the public does not engage in any victim blaming.

"She is 15 and a child. He is 50 - a grown man. She's a high school freshman, he's a former teacher," Gwyn said during a news conference on Tuesday. "This is and was not a romance ... this is not a fairytale, this is a case of kidnapping."

Cummins is believed to be armed with two handguns. He may be driving a silver Nissan Rogue with Tennessee tag 976ZPT.

Because of the relatively low number of tips, agents believe Cummins has hidden Thomas away from the general public. The TBI is encouraging property owners, especially those in rural areas, to search their grounds for Thomas and Cummins, the Nissan Rogue or any suspicious activity.

The TBI is also urging officials at campgrounds, parks or any other isolated areas to remain on alert. They are also asking for people to search large parking lots or garages for Cummins' car.

Investigators said Cummins was last seen in Decatur, AL, just after 3 p.m. Monday, but the TBI said neither Cummins nor Thomas have ties to that area.

"The individuals could, frankly, be anywhere," said the TBI in a news release last week.

Possible sighting of Cummins reported at a gas station in Corpus Christi, TX. Police reviewed surveillance footage and said there was no sign of either Cummins or Thomas. Click here to read more.

- Thursday, March 30:

The Shelby County Sheriff's Office said it identified Cummins in surveillance video from a gas station in Collierville, TN, but the TBI said this sighting was unsubstantiated. Click here to read more.

- Monday, April 3:

The police department in Kearney, NE, reports a possible sighting of Thomas and Cummins. The TBI said this sighting was unsubstantiated. Click here to read more.

Background on Tad Cummins

According to the TBI, investigators have revealed a "troubling pattern of behavior" by Cummins that leads them to believe he may have been abusing his role as a teacher to lure and possibly sexually exploit Thomas.

"We want to remind you, he's 50, she's 15. He was in a position of authority. She was a high school student. We believe this teen is in danger. We want her home. We want him in custody," DeVine said.

A spokesperson for Maury County Schools confirmed Cummins was a teacher at Culleoka Unit School. He was suspended last month due to a sheriff's department investigation and was later fired.

A warrant has been issued for Cummins' arrest for sexual contact with a minor and kidnapping. Officials said the sexual contact charges stems from an incident that occurred at the school between Thomas and Cummins.

According to the TBI, Cummins recently secured a title loan for a personal vehicle totaling $4,500 in cash several days before his disappearance.

Officials said Cummins also recently searched for information online about police being able to track his vehicle and teen marriage.

The Maury County School District released a timeline of the alleged relationship between Thomas and Cummins. Click here to read more.

On Friday, March 31, the attorney for Cummins' wife issued a news release saying she had filed for divorce. Click here to read more.

AMBER ALERT: Here are new pictures of suspect Tad Cummins, captured the week prior to the kidnapping of Elizabeth Thomas. Please RT! pic.twitter.com/CSWajVSiGP

Elizabeth Thomas was new to the Culleoka Unit School in Maury County. She started as a freshman this year, entering the public school system for the very first time. Before that, she was homeschooled.

Channel 4 found that police arrested Elizabeth Thomas' mother, Kimberly Thomas, last year. She was charged with five counts of child abuse and neglect. According to court documents, Kimberly Thomas beat Elizabeth Thomas and four of her siblings.

Elizabeth Thomas told investigators her mother "banged her head into the agitator of the washing machine." She said her mother "threw her down the basement stairs and locked her down there." Click here to read more.

Elizabeth Thomas is one of 10 children in a single-parent home because her father now has full custody of all of them.

Her father, Anthony Thomas, said Cummins had everyone fooled, even school officials. He said after his daughter went missing, he told the school he thought she might be with Cummins.

“When I suggested that to him, he looked at me like I was crazy, like they’ve known him all their life, but I knew," said Anthony Thomas.

Anthony Thomas said before Elizabeth Thomas went missing, things just didn't seem right.

“Things had been a little bit funny, but I couldn’t put my finger on it enough. Something just seemed amiss," he said. Click here to read more.

Her sister, Sarah Thomas, said she heard Cummins tell stories with other students about being in the FBI, CIA and Secret Service.

It wasn’t until allegations spread about Cummins and her sister kissing at school that Sarah Thomas said other students made fun of her.

“She would say, ‘I got to get out of here. We got to leave. We got to get out of here,’” said Sarah Thomas about her sister.

Sarah Thomas told Channel 4 she tried to stop other students from bullying her sister, but it wasn’t enough. Click here to read more.

The victim's brother, James Thomas, said his sister made a disturbing statement the morning she disappeared.

"She told my younger sister that if she wasn't home by 6 o'clock to call the police. Call for help, I think, was her exact words," said James Thomas. Click here to read more.

The Thomas family issued this statement through their attorney on Thursday, March 23:

The last 10 days have been the most difficult in the life of the Thomas family. We want to sincerely thank those of you throughout the country who are praying for Elizabeth's safe and speedy return.

The family has been overwhelmed with the kindness shown to us by the Maury County community and beyond. We humbly ask that you continue to pray as we do our best to cope with the emotional weight of Elizabeth's abduction.

We also thank the press, both local and national, for its continuous coverage of Elizabeth's abduction. It is critical to finding Elizabeth that we broadcast to the widest possible audience so as to keep Elizabeth's story in front of as many people as possible. Hopefully, this awareness will assist law enforcement with tips that will lead to Elizabeth.

The family certainly expresses as well its sincere thanks and praise for law enforcement. The Maury County Sheriff's Department, the District Attorney General's Office for the 22nd Judicial District, the Tennessee Bureau of Investigation, the FBI and other law enforcement agencies have worked tirelessly to find Elizabeth. We ask that the public stay vigilant and provide law enforcement with any information, no matter how insignificant you might perceive it, that could relate to Elizabeth's whereabouts. Law enforcement needs tips.

Finally, we want to also address the Maury County Schools, as the teachers and administration are the core of our community. The Thomas family has the utmost respect and admiration for our teachers. They are the backbone of Maury County. We love Maury County Schools, especially Culleoka.

It is important to the Thomas family to emphasize that none of the reports about possible mistakes regarding Tad Cummins prior to Elizabeth's disappearance are relevant to what we are doing right now. Our focus should be on finding Elizabeth. Period.

To do that, we need as much information as possible, including from the school system. We know that each teacher and administrator of Maury County Schools mourns as we do over this tragedy and wishes daily for Elizabeth's safe return. Despite some of the stories that have been broadcast, the Thomas family wishes to express that the family and the schools are unified in this singular desire. Whatever questions about how issues were handled when Elizabeth was in school are distant and secondary and, in many ways, distracting, to the core issue of finding her. We thank the Maury County School System for its continued help in finding Elizabeth.

We are desperate for any information that might lead to our daughter. The information that we need is not only what people have seen and heard after Elizabeth's disappearance, but also from before. Facts about prior events, especially interaction between Elizabeth and Tad Cummins and statements made by both to third parties, may very well contain clues to lead to Elizabeth's return.

The Thomas family asks that the community in particular revisit events leading to Elizabeth's disappearance and come forward with any information that you believe might give insight into the mind of either Elizabeth or Mr. Cummins. Elizabeth must be found. Time is of the essence.

Thank you, and may God be with Elizabeth.

The Maury County Public School District issued this statement about the situation:

Maury County Public Schools suspended the Culleoka Unit School teacher involved in the law enforcement investigation once we were notified of the allegations. Since then, the teacher has been dismissed as a result of the investigation. The district does not tolerate any manner of behavior that is alleged in this incident and will take swift action to remove parties from school campuses who are involved with investigations of this type.

Below is the surveillance video that the TBI released showing Cummins at a gas station:

This surveillance video shows Cummins at the Walmart in Columbia days before disappearing with Thomas:

This surveillance video shows Cummins at the Walmart in Columbia days before disappearing with Thomas:

Below is a map showing all of the locations involved in the Amber Alert:

The organization predicted 10 to 16 tropical systems, with five to nine becoming hurricanes. One to four of those hurricanes is predicted to develop into major hurricanes of Category 3 strength or above.

The organization predicted 10 to 16 tropical systems, with five to nine becoming hurricanes. One to four of those hurricanes is predicted to develop into major hurricanes of Category 3 strength or above.